dev->get_stats(dev) in COMPAT_NET_DEV_OPS case

dev->get_stats(dev) in COMPAT_NET_DEV_OPS case

[Oliver Hartkopp]

Hello Stephen,

in commit eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0 ("netdev: introduce 
dev_get_stats() 
<http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=commit;h=eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0>")
you remove the setting of dev->get_stats :

@@ -4370,7 
<http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=blob;f=net/core/dev.c;h=ca14ab407b338172758bc409efd2baaf75bdee99;hb=d314774cf2cd5dfeb39a00d37deee65d4c627927#l4370> 
+4384,6 
<http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=blob;f=net/core/dev.c;h=8843f4e3f5e192eba9eb5154faa1ca4131fb01fc;hb=eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0#l4384> 
@@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 
        netdev_init_queues(dev);
 
-       dev->get_stats = internal_stats;
        netpoll_netdev_init(dev);
        setup(dev);
        strcpy(dev->name, name);

I really appreciate your introduction of COMPAT_NET_DEV_OPS but when i 
try to compile and run a non-converted driver, i get a NULL pointer 
dereference. I tracked it down to be the call of dev->get_stats(dev).

Did you miss something or is this behaviour intended?

Regards,
Oliver

Re: dev->get_stats(dev) in COMPAT_NET_DEV_OPS case

[Ben Hutchings]

On Thu, 2009-01-08 at 14:12 +0100, Oliver Hartkopp wrote:
> Hello Stephen,
> 
> in commit eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0 ("netdev: introduce 
> dev_get_stats() 
> <http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=commit;h=eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0>")
> you remove the setting of dev->get_stats :
> 
> @@ -4370,7 
> <http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=blob;f=net/core/dev.c;h=ca14ab407b338172758bc409efd2baaf75bdee99;hb=d314774cf2cd5dfeb39a00d37deee65d4c627927#l4370> 
> +4384,6 
> <http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=blob;f=net/core/dev.c;h=8843f4e3f5e192eba9eb5154faa1ca4131fb01fc;hb=eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0#l4384> 
> @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
>  
>         netdev_init_queues(dev);
>  
> -       dev->get_stats = internal_stats;
>         netpoll_netdev_init(dev);
>         setup(dev);
>         strcpy(dev->name, name);
> 
> I really appreciate your introduction of COMPAT_NET_DEV_OPS but when i 
> try to compile and run a non-converted driver, i get a NULL pointer 
> dereference. I tracked it down to be the call of dev->get_stats(dev).
> 
> Did you miss something or is this behaviour intended?

You should be calling dev_get_stats() now.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: dev->get_stats(dev) in COMPAT_NET_DEV_OPS case

[Oliver Hartkopp]

Ben Hutchings wrote:
> On Thu, 2009-01-08 at 14:12 +0100, Oliver Hartkopp wrote:
>   
>> Hello Stephen,
>>
>> in commit eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0 ("netdev: introduce dev_get_stats()")
>> you remove the setting of dev->get_stats :
>>
>> @@ -4370,7  +4384,6 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
>>  
>>         netdev_init_queues(dev);
>>  
>> -       dev->get_stats = internal_stats;
>>         netpoll_netdev_init(dev);
>>         setup(dev);
>>         strcpy(dev->name, name);
>>
>> I really appreciate your introduction of COMPAT_NET_DEV_OPS but when i 
>> try to compile and run a non-converted driver, i get a NULL pointer 
>> dereference. I tracked it down to be the call of dev->get_stats(dev).
>>
>> Did you miss something or is this behaviour intended?
>>     
>
> You should be calling dev_get_stats() now.
>
>   

I noticed that myself and besides a warning (about the const / non-const 
definition) i got it working again.
But the question remains, if it still makes sense to provide 
dev->get_stats() (referencing to dev_get_stats()) in the 
COMPAT_NET_DEV_OPS case, as i would surely not be the only one tapping 
into this problem ...

Regards,
Oliver

Re: dev->get_stats(dev) in COMPAT_NET_DEV_OPS case

[Stephen Hemminger]

On Thu, 08 Jan 2009 14:12:05 +0100
Oliver Hartkopp <oliver@hartkopp.net> wrote:

> Hello Stephen,
> 
> in commit eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0 ("netdev: introduce 
> dev_get_stats() 
> <http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=commit;h=eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0>")
> you remove the setting of dev->get_stats :
> 
> @@ -4370,7 
> <http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=blob;f=net/core/dev.c;h=ca14ab407b338172758bc409efd2baaf75bdee99;hb=d314774cf2cd5dfeb39a00d37deee65d4c627927#l4370> 
> +4384,6 
> <http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=blob;f=net/core/dev.c;h=8843f4e3f5e192eba9eb5154faa1ca4131fb01fc;hb=eeda3fd64f75bcbfaa70ce946513abaf3f23b8e0#l4384> 
> @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
>  
>         netdev_init_queues(dev);
>  
> -       dev->get_stats = internal_stats;
>         netpoll_netdev_init(dev);
>         setup(dev);
>         strcpy(dev->name, name);
> 
> I really appreciate your introduction of COMPAT_NET_DEV_OPS but when i 
> try to compile and run a non-converted driver, i get a NULL pointer 
> dereference. I tracked it down to be the call of dev->get_stats(dev).

In most cases, drivers shouldn't be call dev->get_stat directly.
I am working to convert all the in-tree uses of get_stats for 2.6.29.
(There are a couple more left).